This invention relates to methods and apparatus for cutting a continuous expanded lead battery grid structure and finds adaptation in the battery grid industry, and in particular, relates to the formation of individually pasted battery grid structures produced therefrom.
The subject invention specifically is addressed to the manufacture of individual storage battery grids having active material embedded within the grid network thereof. Such grid structures are generally made by expanding a metal sheet to form an open network structure and thereafter applying paste thereto by means readily available in the art.
The step of expansion in the process to form the expanded structure may be readily made by conventional processes, such as disclosed in U.S. Pat. No. 3,891,459. After expansion, pasting of the expanded structure is accomplished by moving it into a zone where an active material, generally a thick, lead-containing paste, is applied to the grid network. Various means may be used to apply the active material to the expanded structure. In order to deliver a uniform charge for distribution upon and into the open network of the grid without materially deforming the same, pasting machines are utilized and are generally of the so-called Lund or fixed orifice type or the Winkel or belt type. In the Lund type, a strip of battery paste is fed between a pair of rollers rotating to apply pressure to the grid, the paste being thereby forced into the grid structure. In the Winkel belt type, the grids are fed horizontally on a belt under a roller where the battery paste is applied. Pasting machines have also been developed that use ultrasonic energy to convert battery pastes from their normally nonflowable form to a flowable form. After the expanded structure is subjected to the direct and continuous charge of paste, the pasted grid is moved into a wiping or leveling zone where a doctor blade or the nip of a set of spaced apart rollers produce a uniform paste distribution. In this fashion the paste is compressed by mechanical forces into the interstices of the network, the leveling being such as to merely allow the grid structure itself to freely pass through the zone and undergo only minimum, if any, deformation. Thereafter, the pasted grid is subjected to a drying operation to thereby affix the paste to the network. In a commercial operation, the production of grids is generally made from a large length of sheet material so that there are a multiplicity of grid structures thereon comprising expanded and unexpanded portions. After drying, the structures must be subjected to a separation or cutting operation to sectionalize and set free the individual grids for further processing. Since such structures are more or less in a delicate state, any slitting or cutting must be carefully done so as not to cause loss of paste from the pasted network. It will be appreciated that the battery grids are easily deformable and may lose their character if adequate means are not employed to handle them. Any undue treatment would cause disruption or loss of paste and, therefore, rejection of the grid structure.
Briefly, in accordance with this invention, a cutting apparatus for forming individual battery grid structures from a sheet material having cut out portions therein, said cutting apparatus comprising spaced apart first and second rotatable means, a plurality of leading knives carried by said first means, a plurality of trailing knives carried by said second means, said knives arranged to cut transversely of said material forming shear lines from the edge of said sheet material to the cut out portions of said material, a plurality of blades carried by said first and second rotatable means for cutting longitudinally of said sheet material along a slit line between adjacent cut out portions of said sheet material, said knives and blades being spaced about the periphery of said first and second rotatable means and arranged to cooperate to sectionalize and form thereby individual battery grid structures from said sheet material.
The aforementioned features with the objects and advantages which become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.